warp: Add initial WaRP Board support
[platform/kernel/u-boot.git] / drivers / ddr / fsl / lc_common_dimm_params.c
1 /*
2  * Copyright 2008-2014 Freescale Semiconductor, Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * Version 2 as published by the Free Software Foundation.
7  */
8
9 #include <common.h>
10 #include <fsl_ddr_sdram.h>
11
12 #include <fsl_ddr.h>
13
14 #if defined(CONFIG_SYS_FSL_DDR3) || defined(CONFIG_SYS_FSL_DDR4)
15 static unsigned int
16 compute_cas_latency(const dimm_params_t *dimm_params,
17                     common_timing_params_t *outpdimm,
18                     unsigned int number_of_dimms)
19 {
20         unsigned int i;
21         unsigned int common_caslat;
22         unsigned int caslat_actual;
23         unsigned int retry = 16;
24         unsigned int tmp;
25         const unsigned int mclk_ps = get_memory_clk_period_ps();
26 #ifdef CONFIG_SYS_FSL_DDR3
27         const unsigned int taamax = 20000;
28 #else
29         const unsigned int taamax = 18000;
30 #endif
31
32         /* compute the common CAS latency supported between slots */
33         tmp = dimm_params[0].caslat_x;
34         for (i = 1; i < number_of_dimms; i++) {
35                 if (dimm_params[i].n_ranks)
36                         tmp &= dimm_params[i].caslat_x;
37         }
38         common_caslat = tmp;
39
40         /* validate if the memory clk is in the range of dimms */
41         if (mclk_ps < outpdimm->tckmin_x_ps) {
42                 printf("DDR clock (MCLK cycle %u ps) is faster than "
43                         "the slowest DIMM(s) (tCKmin %u ps) can support.\n",
44                         mclk_ps, outpdimm->tckmin_x_ps);
45         }
46 #ifdef CONFIG_SYS_FSL_DDR4
47         if (mclk_ps > outpdimm->tckmax_ps) {
48                 printf("DDR clock (MCLK cycle %u ps) is slower than DIMM(s) (tCKmax %u ps) can support.\n",
49                        mclk_ps, outpdimm->tckmax_ps);
50         }
51 #endif
52         /* determine the acutal cas latency */
53         caslat_actual = (outpdimm->taamin_ps + mclk_ps - 1) / mclk_ps;
54         /* check if the dimms support the CAS latency */
55         while (!(common_caslat & (1 << caslat_actual)) && retry > 0) {
56                 caslat_actual++;
57                 retry--;
58         }
59         /* once the caculation of caslat_actual is completed
60          * we must verify that this CAS latency value does not
61          * exceed tAAmax, which is 20 ns for all DDR3 speed grades,
62          * 18ns for all DDR4 speed grades.
63          */
64         if (caslat_actual * mclk_ps > taamax) {
65                 printf("The choosen cas latency %d is too large\n",
66                         caslat_actual);
67         }
68         outpdimm->lowest_common_spd_caslat = caslat_actual;
69         debug("lowest_common_spd_caslat is 0x%x\n", caslat_actual);
70
71         return 0;
72 }
73 #else   /* for DDR1 and DDR2 */
74 static unsigned int
75 compute_cas_latency(const dimm_params_t *dimm_params,
76                     common_timing_params_t *outpdimm,
77                     unsigned int number_of_dimms)
78 {
79         int i;
80         const unsigned int mclk_ps = get_memory_clk_period_ps();
81         unsigned int lowest_good_caslat;
82         unsigned int not_ok;
83         unsigned int temp1, temp2;
84
85         debug("using mclk_ps = %u\n", mclk_ps);
86         if (mclk_ps > outpdimm->tckmax_ps) {
87                 printf("Warning: DDR clock (%u ps) is slower than DIMM(s) (tCKmax %u ps)\n",
88                        mclk_ps, outpdimm->tckmax_ps);
89         }
90
91         /*
92          * Compute a CAS latency suitable for all DIMMs
93          *
94          * Strategy for SPD-defined latencies: compute only
95          * CAS latency defined by all DIMMs.
96          */
97
98         /*
99          * Step 1: find CAS latency common to all DIMMs using bitwise
100          * operation.
101          */
102         temp1 = 0xFF;
103         for (i = 0; i < number_of_dimms; i++) {
104                 if (dimm_params[i].n_ranks) {
105                         temp2 = 0;
106                         temp2 |= 1 << dimm_params[i].caslat_x;
107                         temp2 |= 1 << dimm_params[i].caslat_x_minus_1;
108                         temp2 |= 1 << dimm_params[i].caslat_x_minus_2;
109                         /*
110                          * If there was no entry for X-2 (X-1) in
111                          * the SPD, then caslat_x_minus_2
112                          * (caslat_x_minus_1) contains either 255 or
113                          * 0xFFFFFFFF because that's what the glorious
114                          * __ilog2 function returns for an input of 0.
115                          * On 32-bit PowerPC, left shift counts with bit
116                          * 26 set (that the value of 255 or 0xFFFFFFFF
117                          * will have), cause the destination register to
118                          * be 0.  That is why this works.
119                          */
120                         temp1 &= temp2;
121                 }
122         }
123
124         /*
125          * Step 2: check each common CAS latency against tCK of each
126          * DIMM's SPD.
127          */
128         lowest_good_caslat = 0;
129         temp2 = 0;
130         while (temp1) {
131                 not_ok = 0;
132                 temp2 =  __ilog2(temp1);
133                 debug("checking common caslat = %u\n", temp2);
134
135                 /* Check if this CAS latency will work on all DIMMs at tCK. */
136                 for (i = 0; i < number_of_dimms; i++) {
137                         if (!dimm_params[i].n_ranks)
138                                 continue;
139
140                         if (dimm_params[i].caslat_x == temp2) {
141                                 if (mclk_ps >= dimm_params[i].tckmin_x_ps) {
142                                         debug("CL = %u ok on DIMM %u at tCK=%u ps with tCKmin_X_ps of %u\n",
143                                               temp2, i, mclk_ps,
144                                               dimm_params[i].tckmin_x_ps);
145                                         continue;
146                                 } else {
147                                         not_ok++;
148                                 }
149                         }
150
151                         if (dimm_params[i].caslat_x_minus_1 == temp2) {
152                                 unsigned int tckmin_x_minus_1_ps
153                                         = dimm_params[i].tckmin_x_minus_1_ps;
154                                 if (mclk_ps >= tckmin_x_minus_1_ps) {
155                                         debug("CL = %u ok on DIMM %u at tCK=%u ps with tckmin_x_minus_1_ps of %u\n",
156                                               temp2, i, mclk_ps,
157                                               tckmin_x_minus_1_ps);
158                                         continue;
159                                 } else {
160                                         not_ok++;
161                                 }
162                         }
163
164                         if (dimm_params[i].caslat_x_minus_2 == temp2) {
165                                 unsigned int tckmin_x_minus_2_ps
166                                         = dimm_params[i].tckmin_x_minus_2_ps;
167                                 if (mclk_ps >= tckmin_x_minus_2_ps) {
168                                         debug("CL = %u ok on DIMM %u at tCK=%u ps with tckmin_x_minus_2_ps of %u\n",
169                                               temp2, i, mclk_ps,
170                                               tckmin_x_minus_2_ps);
171                                         continue;
172                                 } else {
173                                         not_ok++;
174                                 }
175                         }
176                 }
177
178                 if (!not_ok)
179                         lowest_good_caslat = temp2;
180
181                 temp1 &= ~(1 << temp2);
182         }
183
184         debug("lowest common SPD-defined CAS latency = %u\n",
185               lowest_good_caslat);
186         outpdimm->lowest_common_spd_caslat = lowest_good_caslat;
187
188
189         /*
190          * Compute a common 'de-rated' CAS latency.
191          *
192          * The strategy here is to find the *highest* dereated cas latency
193          * with the assumption that all of the DIMMs will support a dereated
194          * CAS latency higher than or equal to their lowest dereated value.
195          */
196         temp1 = 0;
197         for (i = 0; i < number_of_dimms; i++)
198                 temp1 = max(temp1, dimm_params[i].caslat_lowest_derated);
199
200         outpdimm->highest_common_derated_caslat = temp1;
201         debug("highest common dereated CAS latency = %u\n", temp1);
202
203         return 0;
204 }
205 #endif
206
207 /*
208  * compute_lowest_common_dimm_parameters()
209  *
210  * Determine the worst-case DIMM timing parameters from the set of DIMMs
211  * whose parameters have been computed into the array pointed to
212  * by dimm_params.
213  */
214 unsigned int
215 compute_lowest_common_dimm_parameters(const dimm_params_t *dimm_params,
216                                       common_timing_params_t *outpdimm,
217                                       const unsigned int number_of_dimms)
218 {
219         unsigned int i, j;
220
221         unsigned int tckmin_x_ps = 0;
222         unsigned int tckmax_ps = 0xFFFFFFFF;
223         unsigned int trcd_ps = 0;
224         unsigned int trp_ps = 0;
225         unsigned int tras_ps = 0;
226 #if defined(CONFIG_SYS_FSL_DDR3) || defined(CONFIG_SYS_FSL_DDR4)
227         unsigned int taamin_ps = 0;
228 #endif
229 #ifdef CONFIG_SYS_FSL_DDR4
230         unsigned int twr_ps = 15000;
231         unsigned int trfc1_ps = 0;
232         unsigned int trfc2_ps = 0;
233         unsigned int trfc4_ps = 0;
234         unsigned int trrds_ps = 0;
235         unsigned int trrdl_ps = 0;
236         unsigned int tccdl_ps = 0;
237 #else
238         unsigned int twr_ps = 0;
239         unsigned int twtr_ps = 0;
240         unsigned int trfc_ps = 0;
241         unsigned int trrd_ps = 0;
242         unsigned int trtp_ps = 0;
243 #endif
244         unsigned int trc_ps = 0;
245         unsigned int refresh_rate_ps = 0;
246         unsigned int extended_op_srt = 1;
247 #if defined(CONFIG_SYS_FSL_DDR1) || defined(CONFIG_SYS_FSL_DDR2)
248         unsigned int tis_ps = 0;
249         unsigned int tih_ps = 0;
250         unsigned int tds_ps = 0;
251         unsigned int tdh_ps = 0;
252         unsigned int tdqsq_max_ps = 0;
253         unsigned int tqhs_ps = 0;
254 #endif
255         unsigned int temp1, temp2;
256         unsigned int additive_latency = 0;
257
258         temp1 = 0;
259         for (i = 0; i < number_of_dimms; i++) {
260                 /*
261                  * If there are no ranks on this DIMM,
262                  * it probably doesn't exist, so skip it.
263                  */
264                 if (dimm_params[i].n_ranks == 0) {
265                         temp1++;
266                         continue;
267                 }
268                 if (dimm_params[i].n_ranks == 4 && i != 0) {
269                         printf("Found Quad-rank DIMM in wrong bank, ignored."
270                                 " Software may not run as expected.\n");
271                         temp1++;
272                         continue;
273                 }
274
275                 /*
276                  * check if quad-rank DIMM is plugged if
277                  * CONFIG_CHIP_SELECT_QUAD_CAPABLE is not defined
278                  * Only the board with proper design is capable
279                  */
280 #ifndef CONFIG_FSL_DDR_FIRST_SLOT_QUAD_CAPABLE
281                 if (dimm_params[i].n_ranks == 4 && \
282                   CONFIG_CHIP_SELECTS_PER_CTRL/CONFIG_DIMM_SLOTS_PER_CTLR < 4) {
283                         printf("Found Quad-rank DIMM, not able to support.");
284                         temp1++;
285                         continue;
286                 }
287 #endif
288                 /*
289                  * Find minimum tckmax_ps to find fastest slow speed,
290                  * i.e., this is the slowest the whole system can go.
291                  */
292                 tckmax_ps = min(tckmax_ps,
293                                 (unsigned int)dimm_params[i].tckmax_ps);
294 #if defined(CONFIG_SYS_FSL_DDR3) || defined(CONFIG_SYS_FSL_DDR4)
295                 taamin_ps = max(taamin_ps,
296                                 (unsigned int)dimm_params[i].taa_ps);
297 #endif
298                 tckmin_x_ps = max(tckmin_x_ps,
299                                   (unsigned int)dimm_params[i].tckmin_x_ps);
300                 trcd_ps = max(trcd_ps, (unsigned int)dimm_params[i].trcd_ps);
301                 trp_ps = max(trp_ps, (unsigned int)dimm_params[i].trp_ps);
302                 tras_ps = max(tras_ps, (unsigned int)dimm_params[i].tras_ps);
303 #ifdef CONFIG_SYS_FSL_DDR4
304                 trfc1_ps = max(trfc1_ps,
305                                (unsigned int)dimm_params[i].trfc1_ps);
306                 trfc2_ps = max(trfc2_ps,
307                                (unsigned int)dimm_params[i].trfc2_ps);
308                 trfc4_ps = max(trfc4_ps,
309                                (unsigned int)dimm_params[i].trfc4_ps);
310                 trrds_ps = max(trrds_ps,
311                                (unsigned int)dimm_params[i].trrds_ps);
312                 trrdl_ps = max(trrdl_ps,
313                                (unsigned int)dimm_params[i].trrdl_ps);
314                 tccdl_ps = max(tccdl_ps,
315                                (unsigned int)dimm_params[i].tccdl_ps);
316 #else
317                 twr_ps = max(twr_ps, (unsigned int)dimm_params[i].twr_ps);
318                 twtr_ps = max(twtr_ps, (unsigned int)dimm_params[i].twtr_ps);
319                 trfc_ps = max(trfc_ps, (unsigned int)dimm_params[i].trfc_ps);
320                 trrd_ps = max(trrd_ps, (unsigned int)dimm_params[i].trrd_ps);
321                 trtp_ps = max(trtp_ps, (unsigned int)dimm_params[i].trtp_ps);
322 #endif
323                 trc_ps = max(trc_ps, (unsigned int)dimm_params[i].trc_ps);
324 #if defined(CONFIG_SYS_FSL_DDR1) || defined(CONFIG_SYS_FSL_DDR2)
325                 tis_ps = max(tis_ps, (unsigned int)dimm_params[i].tis_ps);
326                 tih_ps = max(tih_ps, (unsigned int)dimm_params[i].tih_ps);
327                 tds_ps = max(tds_ps, (unsigned int)dimm_params[i].tds_ps);
328                 tdh_ps = max(tdh_ps, (unsigned int)dimm_params[i].tdh_ps);
329                 tqhs_ps = max(tqhs_ps, (unsigned int)dimm_params[i].tqhs_ps);
330                 /*
331                  * Find maximum tdqsq_max_ps to find slowest.
332                  *
333                  * FIXME: is finding the slowest value the correct
334                  * strategy for this parameter?
335                  */
336                 tdqsq_max_ps = max(tdqsq_max_ps,
337                                    (unsigned int)dimm_params[i].tdqsq_max_ps);
338 #endif
339                 refresh_rate_ps = max(refresh_rate_ps,
340                                       (unsigned int)dimm_params[i].refresh_rate_ps);
341                 /* extended_op_srt is either 0 or 1, 0 having priority */
342                 extended_op_srt = min(extended_op_srt,
343                                       (unsigned int)dimm_params[i].extended_op_srt);
344         }
345
346         outpdimm->ndimms_present = number_of_dimms - temp1;
347
348         if (temp1 == number_of_dimms) {
349                 debug("no dimms this memory controller\n");
350                 return 0;
351         }
352
353         outpdimm->tckmin_x_ps = tckmin_x_ps;
354         outpdimm->tckmax_ps = tckmax_ps;
355 #if defined(CONFIG_SYS_FSL_DDR3) || defined(CONFIG_SYS_FSL_DDR4)
356         outpdimm->taamin_ps = taamin_ps;
357 #endif
358         outpdimm->trcd_ps = trcd_ps;
359         outpdimm->trp_ps = trp_ps;
360         outpdimm->tras_ps = tras_ps;
361 #ifdef CONFIG_SYS_FSL_DDR4
362         outpdimm->trfc1_ps = trfc1_ps;
363         outpdimm->trfc2_ps = trfc2_ps;
364         outpdimm->trfc4_ps = trfc4_ps;
365         outpdimm->trrds_ps = trrds_ps;
366         outpdimm->trrdl_ps = trrdl_ps;
367         outpdimm->tccdl_ps = tccdl_ps;
368 #else
369         outpdimm->twtr_ps = twtr_ps;
370         outpdimm->trfc_ps = trfc_ps;
371         outpdimm->trrd_ps = trrd_ps;
372         outpdimm->trtp_ps = trtp_ps;
373 #endif
374         outpdimm->twr_ps = twr_ps;
375         outpdimm->trc_ps = trc_ps;
376         outpdimm->refresh_rate_ps = refresh_rate_ps;
377         outpdimm->extended_op_srt = extended_op_srt;
378 #if defined(CONFIG_SYS_FSL_DDR1) || defined(CONFIG_SYS_FSL_DDR2)
379         outpdimm->tis_ps = tis_ps;
380         outpdimm->tih_ps = tih_ps;
381         outpdimm->tds_ps = tds_ps;
382         outpdimm->tdh_ps = tdh_ps;
383         outpdimm->tdqsq_max_ps = tdqsq_max_ps;
384         outpdimm->tqhs_ps = tqhs_ps;
385 #endif
386
387         /* Determine common burst length for all DIMMs. */
388         temp1 = 0xff;
389         for (i = 0; i < number_of_dimms; i++) {
390                 if (dimm_params[i].n_ranks) {
391                         temp1 &= dimm_params[i].burst_lengths_bitmask;
392                 }
393         }
394         outpdimm->all_dimms_burst_lengths_bitmask = temp1;
395
396         /* Determine if all DIMMs registered buffered. */
397         temp1 = temp2 = 0;
398         for (i = 0; i < number_of_dimms; i++) {
399                 if (dimm_params[i].n_ranks) {
400                         if (dimm_params[i].registered_dimm) {
401                                 temp1 = 1;
402 #ifndef CONFIG_SPL_BUILD
403                                 printf("Detected RDIMM %s\n",
404                                         dimm_params[i].mpart);
405 #endif
406                         } else {
407                                 temp2 = 1;
408 #ifndef CONFIG_SPL_BUILD
409                                 printf("Detected UDIMM %s\n",
410                                         dimm_params[i].mpart);
411 #endif
412                         }
413                 }
414         }
415
416         outpdimm->all_dimms_registered = 0;
417         outpdimm->all_dimms_unbuffered = 0;
418         if (temp1 && !temp2) {
419                 outpdimm->all_dimms_registered = 1;
420         } else if (!temp1 && temp2) {
421                 outpdimm->all_dimms_unbuffered = 1;
422         } else {
423                 printf("ERROR:  Mix of registered buffered and unbuffered "
424                                 "DIMMs detected!\n");
425         }
426
427         temp1 = 0;
428         if (outpdimm->all_dimms_registered)
429                 for (j = 0; j < 16; j++) {
430                         outpdimm->rcw[j] = dimm_params[0].rcw[j];
431                         for (i = 1; i < number_of_dimms; i++) {
432                                 if (!dimm_params[i].n_ranks)
433                                         continue;
434                                 if (dimm_params[i].rcw[j] != dimm_params[0].rcw[j]) {
435                                         temp1 = 1;
436                                         break;
437                                 }
438                         }
439                 }
440
441         if (temp1 != 0)
442                 printf("ERROR: Mix different RDIMM detected!\n");
443
444         /* calculate cas latency for all DDR types */
445         if (compute_cas_latency(dimm_params, outpdimm, number_of_dimms))
446                 return 1;
447
448         /* Determine if all DIMMs ECC capable. */
449         temp1 = 1;
450         for (i = 0; i < number_of_dimms; i++) {
451                 if (dimm_params[i].n_ranks &&
452                         !(dimm_params[i].edc_config & EDC_ECC)) {
453                         temp1 = 0;
454                         break;
455                 }
456         }
457         if (temp1) {
458                 debug("all DIMMs ECC capable\n");
459         } else {
460                 debug("Warning: not all DIMMs ECC capable, cant enable ECC\n");
461         }
462         outpdimm->all_dimms_ecc_capable = temp1;
463
464         /*
465          * Compute additive latency.
466          *
467          * For DDR1, additive latency should be 0.
468          *
469          * For DDR2, with ODT enabled, use "a value" less than ACTTORW,
470          *      which comes from Trcd, and also note that:
471          *          add_lat + caslat must be >= 4
472          *
473          * For DDR3, we use the AL=0
474          *
475          * When to use additive latency for DDR2:
476          *
477          * I. Because you are using CL=3 and need to do ODT on writes and
478          *    want functionality.
479          *    1. Are you going to use ODT? (Does your board not have
480          *      additional termination circuitry for DQ, DQS, DQS_,
481          *      DM, RDQS, RDQS_ for x4/x8 configs?)
482          *    2. If so, is your lowest supported CL going to be 3?
483          *    3. If so, then you must set AL=1 because
484          *
485          *       WL >= 3 for ODT on writes
486          *       RL = AL + CL
487          *       WL = RL - 1
488          *       ->
489          *       WL = AL + CL - 1
490          *       AL + CL - 1 >= 3
491          *       AL + CL >= 4
492          *  QED
493          *
494          *  RL >= 3 for ODT on reads
495          *  RL = AL + CL
496          *
497          *  Since CL aren't usually less than 2, AL=0 is a minimum,
498          *  so the WL-derived AL should be the  -- FIXME?
499          *
500          * II. Because you are using auto-precharge globally and want to
501          *     use additive latency (posted CAS) to get more bandwidth.
502          *     1. Are you going to use auto-precharge mode globally?
503          *
504          *        Use addtivie latency and compute AL to be 1 cycle less than
505          *        tRCD, i.e. the READ or WRITE command is in the cycle
506          *        immediately following the ACTIVATE command..
507          *
508          * III. Because you feel like it or want to do some sort of
509          *      degraded-performance experiment.
510          *     1.  Do you just want to use additive latency because you feel
511          *         like it?
512          *
513          * Validation:  AL is less than tRCD, and within the other
514          * read-to-precharge constraints.
515          */
516
517         additive_latency = 0;
518
519 #if defined(CONFIG_SYS_FSL_DDR2)
520         if ((outpdimm->lowest_common_spd_caslat < 4) &&
521             (picos_to_mclk(trcd_ps) > outpdimm->lowest_common_spd_caslat)) {
522                 additive_latency = picos_to_mclk(trcd_ps) -
523                                    outpdimm->lowest_common_spd_caslat;
524                 if (mclk_to_picos(additive_latency) > trcd_ps) {
525                         additive_latency = picos_to_mclk(trcd_ps);
526                         debug("setting additive_latency to %u because it was "
527                                 " greater than tRCD_ps\n", additive_latency);
528                 }
529         }
530 #endif
531
532         /*
533          * Validate additive latency
534          *
535          * AL <= tRCD(min)
536          */
537         if (mclk_to_picos(additive_latency) > trcd_ps) {
538                 printf("Error: invalid additive latency exceeds tRCD(min).\n");
539                 return 1;
540         }
541
542         /*
543          * RL = CL + AL;  RL >= 3 for ODT_RD_CFG to be enabled
544          * WL = RL - 1;  WL >= 3 for ODT_WL_CFG to be enabled
545          * ADD_LAT (the register) must be set to a value less
546          * than ACTTORW if WL = 1, then AL must be set to 1
547          * RD_TO_PRE (the register) must be set to a minimum
548          * tRTP + AL if AL is nonzero
549          */
550
551         /*
552          * Additive latency will be applied only if the memctl option to
553          * use it.
554          */
555         outpdimm->additive_latency = additive_latency;
556
557         debug("tCKmin_ps = %u\n", outpdimm->tckmin_x_ps);
558         debug("trcd_ps   = %u\n", outpdimm->trcd_ps);
559         debug("trp_ps    = %u\n", outpdimm->trp_ps);
560         debug("tras_ps   = %u\n", outpdimm->tras_ps);
561 #ifdef CONFIG_SYS_FSL_DDR4
562         debug("trfc1_ps = %u\n", trfc1_ps);
563         debug("trfc2_ps = %u\n", trfc2_ps);
564         debug("trfc4_ps = %u\n", trfc4_ps);
565         debug("trrds_ps = %u\n", trrds_ps);
566         debug("trrdl_ps = %u\n", trrdl_ps);
567         debug("tccdl_ps = %u\n", tccdl_ps);
568 #else
569         debug("twtr_ps   = %u\n", outpdimm->twtr_ps);
570         debug("trfc_ps   = %u\n", outpdimm->trfc_ps);
571         debug("trrd_ps   = %u\n", outpdimm->trrd_ps);
572 #endif
573         debug("twr_ps    = %u\n", outpdimm->twr_ps);
574         debug("trc_ps    = %u\n", outpdimm->trc_ps);
575
576         return 0;
577 }